Lyretail Anthias Harem happening

[Jeffcb]

I added 5 Blue Eyed Sea Goldie's about 5 months ago. They were all about the same size give or take a little.
It looks like one of them is becoming a male! They all get along except for the smallest one. The chase her the most and she stays at one end of the tank usually.
Its hard to get them to sit still for pics ha ha but he is getting a white belly , turning red and its dorsal fin spine is growing longer. Here are some pics

When should I get the nursery ready?

 

[vetteguy53081]

Unfortunately, typical anthias aggression that often results in death. If any damage occurs, consider acclimation box for the small one for a few days

 

[jdiefenbaugh]

They will all turn male, eventually, and harass each other. I usually don't have death or real damage between lyre tails, however.